Various automotive component parts are inevitably subjected to vibrations and impacts as the vehicle travels over irregular road surfaces. Conversely, component parts such as electric motors and fluid pipes that produce vibrations and impacts are mounted on the vehicle body. In either case, it is often necessary to prevent the vibrations and impacts from being transmitted from the vehicle body to the component parts or from the component part to the vehicle body. For this purpose, it is often practiced to support the component part on the vehicle body via a rubber mount which resiliently supports the component part and insulates the vibrations and impacts.
JP2002-13590 discloses a rubber mount of this kind. A cylindrical rubber member is provided with an annular groove on the outer circumferential surface thereof, and the edge of the component part surrounding an opening thereof is fitted into the annular groove. The rubber member is provided with a central axial bore, and a tubular collar is placed in the central axial bore. A threaded bolt is passed through the central bore of the tubular collar and threaded into a threaded opening of the vehicle body so that the component part is supported by the vehicle body via the rubber member, and the compressive load that is applied to the rubber member by the threaded bold is controlled by the tubular collar. The length of the collar is related to the axial length of the rubber member such that a prescribed compressive load is applied to the rubber member.
This prior art provides a reasonable insulation of vibrations and impacts between the vehicle body and the component part, but is accompanied by a few disadvantages. First of all, the need of the collar in addition to the rubber member and the threaded bolt increases the number of necessary component parts, and complicates the assembly process. If the collar is inadvertently omitted, the axial load on the rubber member cannot be properly set, and the rubber mount is unable to function properly.
In the design of a rubber mount, it is important that the component part to be supported is adequately firmly supported so as not to be displaced excessively or unpredictably (or to be even dislodged from the rubber mount), but is required to be adequately resiliently supported in order to achieve a desired vibration insulation performance.